The objective of the proposed research is to elucidate the sites and mechanisms of neuroendocrine interaction as related to adrenocortical function and thus to stress response. To this end, the following experiments will be conducted: 1) Study of the effects of selective brain lesions and hypothalamic deafferentation on adrenocortical responses to sensory stimuli in order to elucidate the neural pathways which mediate these responses. 2) Investigation of the sites of action of the glucocorticoids in the negative feedback regulation of ACTH secretion, by studying the effect of hormones in animals with selective brain lesions and partial hypothalamic deafferentation. 3) Identification by electrophysiological methods, of the neural inputs from extrahypothalamic limbic structures to the mediobasal hypothalamus. 4) Investigation of intracellularly recorded effects of extra-cellularly iontophorised glucocorticoids on hippocampal neurons, in order to understand the mechanisms underlying the action of these hormones on neuronal excitability.